Oi on Terminal

Introduction to CP Maker

Sat, 04 Apr 2026 15:36:04 +0800

项目地址：https://github.com/Enucai/CP-Maker。

这是一个帮你为算法竞赛题目造数据的项目。本项目大部分由 GPT-5.3-Codex 生成。

写这个项目的原因是要搬模拟赛，但是不想自己造数据了，一些比较简单的题造菜一点的数据也没啥关系，所以让 ai 造一下得了。

你只需要提供题目描述，输入输出格式，数据范围和 std，项目可以自动生成 testlib 格式的 generator, validator 和 checker，然后批量生成输入输出文件。当然如果你能够提供题目解法，生成效果可能会更好。

同时，如果你要卡一部分做法，你也可以提供额外的提示词，让 AI 帮你造一些更强的数据。

项目支持直接将数据打包成 UOJ 格式，略去了人工写 problem.conf 的过程。

相信只要你使用的模型足够强，那么生成的数据就能足够强。

目前用 grok-4.1-fast 并非 coding 模型来造「联合省选 2026 recollector」的数据，能够生成与官方数据强度类似的数据（）。当然我没有免费的 api key 可以用，所以用的模型都比较菜。有钱的可以用更强的模型试试。

接下来的一些更新方向：

添加 subtask 的支持，从而更加适配 OI 题目的要求。（已更新 @ 2026.4.4 18:45）

欢迎提交 Issues 或 PR。

Union and Intersection of Tree and Path Neighborhoods

Sat, 10 Jan 2026 16:38:07 +0800

This article is the author’s National Training Team paper.

Abstract

This paper introduces the theory of tree neighborhoods, methods for finding the union and intersection of tree neighborhoods, and the theory and algorithms for the intersection of path neighborhoods on trees. Furthermore, it presents several applications of these methods to related problems.

Introduction

Tree-structured problems are crucial subjects of study in algorithmic competitions, among which tree neighborhood problems are highly common.

Introduction to Y-Fast Trie

Mon, 08 Dec 2025 23:38:36 +0800

This is my presentation slides for a data structures and algorithms presentation, which introduces the Y-Fast Trie algorithm.

Or open the PDF file here to view: Y-Fast Trie Algorithm.pdf。

My OI Memoirs

Thu, 13 Nov 2025 00:00:00 +0800

Preface

Looking back at the path I have traveled, it has already been six years since my very first encounter with Informatics Olympiad. These six years have felt like a long, burning journey—countless early mornings and late nights, and innumerable moments of my fingers raining down on the keyboard in front of the screen have interwoven to form the most unique imprint of my youth.

In those many competitions, I have tasted the joy of success and experienced the dark valleys of disappointment. Today, standing on the threshold of eighteen, I pick up my pen to write down these words. This is both a tribute to those past days and nights that I couldn’t bear to part with, and a coming-of-age gift to myself—a gift belonging to that young boy who refused to give up and still harbors dreams.

My Self-Authored Algorithm Problems

Fri, 10 Oct 2025 21:52:33 +0800

Codeforces Global Round 28 B. Kevin and Permutation https://codeforces.com/contest/2048/problem/B
Codeforces Global Round 28 F. Kevin and Math Class https://codeforces.com/contest/2048/problem/F
2025 Multi-University Training Contest 10 G. Message Spreading https://acm.hdu.edu.cn/showproblem.php?pid=8093
2025 Multi-University Training Contest 10 L. Counting Colorful Sequence https://acm.hdu.edu.cn/showproblem.php?pid=8098
Pan African Informatics Olympiad 2025 Day 1 D. XOR Multiset https://qoj.ac/contest/2525/problem/14517
Secret Source 登山计划 https://zhengruioi.com/problem/3387